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40 Dr . Pear son's Experiments and Observations. 
concretions of other brute animals, especially with those of the 
horse. - 
The specific gravity of the present calculus was 1,7. 
That of one from the urinary bladder of the human subject, 
of the sort called mulberry calculus, and which consisted almost 
entirely of uric oxide, was 1 ,6og. 
That of another human urinary concretion, of the same com- 
position as the former, but quite smooth, extracted by Mr. Ford, 
was 1,571. 
1 . The present calculus of the dog had no taste, nor smell, 
till exposed to fire. 
2. Under the blowpipe it first became black, and emitted 
the smell of common animal matter ; it next smelt strongly of 
empyreumatic liquor cornu cervi ; and, afterburning some time, 
became inodorous, and white, and readily melted, like super- 
phosphate of lime. 
3. On trituration with lye of caustic soda, there was a copious 
discharge of ammoniac. 
4. It dissolved, on boiling in nitric acid : the solution was 
clear and colourless ; and, on evaporation to dryness, left a re- 
sidue of white bitter matter, which, under the blowpipe emitted, 
weakly, the smell of animal matter. 
5. Upon distilling a mixture of 150 grains of this concretion 
pulverized and two pints and a half of pure water, to three 
ounces, the distilled liquid was found to contain nothing but a 
little ammoniac. The three ounces of residuary liquid, being fil- 
trated and evaporated, yielded 20 grains of phosphate of ammo- 
niac, with a little animal matter ; and the residuary undissolved 
matter amounted to 67 grains. 
6. These 67 grains, being triturated with four ounces of caustic 
